Cryptology ePrint Archive: Report 2013/661

Private aggregation on untrusted servers with customizable thresholds

Constantinos Patsakis, Michael Clear, Paul Laird

Abstract: While multiparty computations are becoming more and more efficient, their performance has not yet reached the level needed to be widely deployed for many applications. Nevertheless, the heterogeneous environment of modern computing needs this functionality in order to provide users their right to privacy. For a wide range of applications there is no need for complex computations; operations such as multiplication or addition might be sufficient. In this work we introduce a new multiparty computation protocol (MPC) for multi-round summation whose security is based on DDH in the semihonest model. We also introduce the concept of an anonymous aggregation system that combines MPC with ``blinded'' aggregation so that the aggregate values may remain hidden from the aggregator, and show how to achieve this with our MPC protocol. We give results on the performance of our solution and discuss suitable applications.